Commit fa466c91 authored by Franklin S Cooper Jr's avatar Franklin S Cooper Jr Committed by Mark Brown
Browse files

spi: davinci: Choose correct pre-scaler limit based on SOC 



Currently the pre-scaler limit is incorrect. The value differs slightly
for various devices so a single value can't be used. Using the compatible
field select the correct pre-scaler limit.

Add new compatible field value for Keystone devices to support their
unique pre-scaler limit value.

Signed-off-by: default avatarFranklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: default avatarSekhar Nori <nsekhar@ti.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent bba732d8

Documentation/devicetree/bindings/spi/spi-davinci.txt

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ Required properties: 
- compatible:

	- "ti,dm6441-spi" for SPI used similar to that on DM644x SoC family

	- "ti,da830-spi" for SPI used similar to that on DA8xx SoC family

	- "ti,keystone-spi" for SPI used similar to that on Keystone2 SoC

		family

- reg: Offset and length of SPI controller register space

- num-cs: Number of chip selects. This includes internal as well as

	GPIO chip selects.

drivers/spi/spi-davinci.c

+36 −7
Original line number Diff line number Diff line
@@ -139,6 +139,8 @@ struct davinci_spi { 
	u32			(*get_tx)(struct davinci_spi *);



	u8			*bytes_per_word;



	u8			prescaler_limit;

};



static struct davinci_spi_config davinci_spi_default_cfg;
@@ -266,7 +268,7 @@ static inline int davinci_spi_get_prescale(struct davinci_spi *dspi, 
	/* Subtract 1 to match what will be programmed into SPI register. */

	ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz) - 1;



	if (ret < 0 || ret > 255)

	if (ret < dspi->prescaler_limit || ret > 255)

		return -EINVAL;



	return ret;
@@ -833,13 +835,40 @@ rx_dma_failed: 
}



#if defined(CONFIG_OF)



/* OF SPI data structure */

struct davinci_spi_of_data {

	u8	version;

	u8	prescaler_limit;

};



static const struct davinci_spi_of_data dm6441_spi_data = {

	.version = SPI_VERSION_1,

	.prescaler_limit = 2,

};



static const struct davinci_spi_of_data da830_spi_data = {

	.version = SPI_VERSION_2,

	.prescaler_limit = 2,

};



static const struct davinci_spi_of_data keystone_spi_data = {

	.version = SPI_VERSION_1,

	.prescaler_limit = 0,

};



static const struct of_device_id davinci_spi_of_match[] = {

	{

		.compatible = "ti,dm6441-spi",

		.data = &dm6441_spi_data,

	},

	{

		.compatible = "ti,da830-spi",

		.data = (void *)SPI_VERSION_2,

		.data = &da830_spi_data,

	},

	{

		.compatible = "ti,keystone-spi",

		.data = &keystone_spi_data,

	},

	{ },

};
@@ -858,21 +887,21 @@ static int spi_davinci_get_pdata(struct platform_device *pdev, 
			struct davinci_spi *dspi)

{

	struct device_node *node = pdev->dev.of_node;

	struct davinci_spi_of_data *spi_data;

	struct davinci_spi_platform_data *pdata;

	unsigned int num_cs, intr_line = 0;

	const struct of_device_id *match;



	pdata = &dspi->pdata;



	pdata->version = SPI_VERSION_1;

	match = of_match_device(davinci_spi_of_match, &pdev->dev);

	if (!match)

		return -ENODEV;



	/* match data has the SPI version number for SPI_VERSION_2 */

	if (match->data == (void *)SPI_VERSION_2)

		pdata->version = SPI_VERSION_2;

	spi_data = (struct davinci_spi_of_data *)match->data;



	pdata->version = spi_data->version;

	pdata->prescaler_limit = spi_data->prescaler_limit;

	/*

	 * default num_cs is 1 and all chipsel are internal to the chip

	 * indicated by chip_sel being NULL or cs_gpios being NULL or
@@ -992,7 +1021,7 @@ static int davinci_spi_probe(struct platform_device *pdev) 


	dspi->bitbang.chipselect = davinci_spi_chipselect;

	dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;



	dspi->prescaler_limit = pdata->prescaler_limit;

	dspi->version = pdata->version;



	dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP;

include/linux/platform_data/spi-davinci.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ struct davinci_spi_platform_data { 
	u8			num_chipselect;

	u8			intr_line;

	u8			*chip_sel;

	u8			prescaler_limit;

	bool			cshold_bug;

	enum dma_event_q	dma_event_q;

};

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